Which motives drive the decision of a voter to approve or reject a policy proposal? The Public Choice literature distinguishes between instrumental and expressive voting motives. We investigate the importance of these motives by analysing the patterns of neural activity in different voting situations. We conduct an fMRI-experiment which investigates neural activation at the moment of voting and use the altruism scale proposed by Tankersley et al. (2007) to differentiate between altruists and non-altruists. Non-altruists show neural activation patterns that are consistent with expressive voting motives. Among non-altruists, we also find activation patterns that point at egoistic instrumental motives. Both results are in line with the corresponding Public Choice literature. On the other hand, we find no evidence for expressive voting motives among altruists. Their neural activation pattern is generally much less conclusive with respect to the underlying motives.